Aluminum alloys and anodized aluminum due to their unique properties and low cost have been widely applied as plasma etch chamber part coatings, stripping chambers, and process kits since the 1980s. In addition, it is anticipated that they will continue to serve either as plasma etching chamber coatings or stripping chambers in the future.
With the etching feature size shrinkage up to 45 nm, 32 nm, and even 25 nm as well as new etching applications, the decontamination and surface cleanliness of aluminum and anodized aluminum have become an important factor for achieving a high production yield in silicon wafer fabrication. Therefore, it would desirable to have an enhanced precision wet cleaning on both aluminum and anodized aluminum in order to achieve zero particles, low transition metal contamination and mobile ion levels such as Na (sodium) and K (potassium) without causing the corrosion of bare and/or underlying aluminum and the degradation of the unique property of anodized aluminum.
The existing precision wet cleaning procedures of bare aluminum and anodized aluminum including the on-line and off-line precision wet cleaning procedures have been performed for many years in the semiconductor industry. However, the relatively high metal contamination levels on bare aluminum and the anodized aluminum surfaces, which did not attract technical attention in the past, has been shown to cause productivity issues on etch tools. Every supplier generally has its own wet cleaning method to clean bare aluminum and anodized aluminum. In most cases, the surface cleanliness is poor and inconsistent. In addition, suppliers have no methodology to evaluate the chemical compatibility of bare aluminum and anodized aluminum after exposure to different chemicals. The quantitative data to support surface cleanliness after cleaning is also not available.
A number of issues exist including that the wet cleaning suppliers in the world lack facilities and techniques to carry on the characterization of anodized aluminum before and after precision wet cleaning. For example, at this time, it is believed that only the United States and Japan have the facilities to perform these studies. Furthermore, previous wet cleaning methods or procedures of bare aluminum and anodized aluminum cannot provide a consistent surface cleanliness on both bare aluminum and anodized aluminum. For etching of small feature sizes and new etch applications, the previously existing cleaning methods provide high levels of mobile ions and transition metals on bare aluminum and anodized aluminum. Therefore, the production yield may be impacted by high metal contamination levels.
Furthermore, manufacturers that are working on small etching feature sizes and new etch applications usually face the challenges of high levels of Na and K, as well as other transition metals on the production wafers. A high level of metal contamination on the aluminum and anodized aluminum chamber parts can cause production yield losses unless the metal contamination is removed.
Accordingly, it would be desirable to have a system and method of cleaning a component of a plasma chamber, wherein the component has an aluminum or anodized aluminum surface, which address the problems mentioned above.